The invention relates to valves for control of fluid flow, wherein a valve member is operated via a brushless DC motor actuator that is integrated with the valve member.
Related Pat. Nos. 4,892,286 and 4,930,746 disclose technology wherein an integrated brushless DC motor-actuator directly operates a fluid-flow control element. These patents are concerned with techniques to convert the rotary motion and torque of the motor into axial motion and force, to actuate a poppet-style flow-control element. These patents require continuous application of electrical power in at least one valve position, so that these patented valves are at a disadvantage in situations wherein only an absolute minimum of electric-power consumption is to be tolerated. Moreover, the mechanical structure to accomplish conversion of rotary to axial displacement is relatively complex, expensive and unduly dependent upon manufacturing tolerances.